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Pegmatite identification and geology

An exceptionally coarse-grained igneous rock, typically of granitic composition, with crystals generally exceeding 1 cm and sometimes reaching several meters in length. Pegmatites form from the last volatile-rich fraction of a crystallizing magma and are important sources of lithium, beryllium, tantalum, cesium, gemstones tourmaline, beryl, topaz , and industrial minerals feldspar, quartz, mica . Field: petrology. Example: The Tanco pegmatite at Bernic Lake, Manitoba, contains spectacular crystals of spodumene, pollucite, and tantalite, and is one of the world's most important sources of tantalum and cesium.. Related terms: Granite, Volatile, Rare earth elements, Spodumene.

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Sources, scope & corrections

These authoritative resources support category-level nomenclature, terminology, identification methods, and safety. When a specimen-specific safety warning appears, the public-health source listed here directly supports that precaution. They are not line-by-line citations for every other property on this entry, and natural specimens vary.

Editorial owner
GeoMiner
Last updated
2026-03-30T15:19:42.055955+00:00
Review status
Published; not independently peer-reviewed
  • USGS Thesaurus — U.S. Geological Survey. Controlled earth-science terminology used to describe USGS information resources.
  • Glossary of Geologic Terms — U.S. National Park Service. Geologic definitions prepared by the NPS Geologic Resources Inventory.

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Common questions

What does Pegmatite mean in geology?
An exceptionally coarse-grained igneous rock, typically of granitic composition, with crystals generally exceeding 1 cm and sometimes reaching several meters in length. Pegmatites form from the last volatile-rich fraction of a crystallizing magma and are important sources of lithium, beryllium, tantalum, cesium, gemstones tourmaline, beryl, topaz , and industrial minerals feldspar, quartz, mica .
What is an example of Pegmatite?
The Tanco pegmatite at Bernic Lake, Manitoba, contains spectacular crystals of spodumene, pollucite, and tantalite, and is one of the world's most important sources of tantalum and cesium.
Which earth-science field uses the term Pegmatite?
Pegmatite is used in petrology.
Which terms are related to Pegmatite?
Related terms in this reference are Granite, Volatile, Rare earth elements, Spodumene.

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